Assuming I am understanding you correctly, how do wrist locks fit into this view of aikido?

I think the key is the word itself: it is not wrist pain or wrist hurt, but wrist lock. If you very slowly apply and study the body mechanics, a properly applied wrist lock will progressively move up the body, locking the elbow, locking and raising the shoulder, and connecting to the person's center. It will only HURT if the person moves against it rather than with it.